Diels-Alder反应在硅橡胶工业及聚硅烷化学中的应用

本文总结了Diels—Alder反应在硅橡胶加工和聚硅烷合成方面的应用,其中包括:(一) 利用该反应合成了含多苯苯基或稠环的硅橡胶交联剂和耐热助剂;(二) 通过该反应建立了硅橡胶新型硫化体系,不外加催化剂;(三) 通过该反应合成了含多苯苯基或稠环的有机硅单体,进而制出许多新型聚硅烷;(四) 探讨了影响硅橡胶各种性能的因素及大芳基对聚硅烷性能的影响。     

甲基二氯硅烷缩合反应的研究

由于聚硅烷具有一些特殊的性质及用途,近年来引起了人们的注意。文献报道的多是主链连有烷基、芳基或芳烷基的聚硅烷,而主链连有活性基团的聚硅烷很少。我们曾合成了主链连有硅氢基团的聚硅烷,并研究了其交联反应。通过硅氢键的反应,可在硅一硅主链上引入一些活性基团,赋予聚硅烷新的特性。本文则报道不同反应条件对甲基二氯硅烷缩合的影响。     

聚硅烷研究进展 (1)聚硅烷的合成及应用

聚硅烷的合成及应用因可溶性聚硅烷的发现而成为聚合物研究的又一热点。本文综述了聚硅烷合成与应用的近期发展。     

聚硅烷的电化学合成

聚硅烷是一类链骨架中仅含硅原子的高聚物,主链的上的非定域σ键电子赋予了聚硅烷独特的光电性质,也是制备陶瓷材料的先驱体。电化学法是最近兴起且具发展前景的一种合成聚硅烷的方法,它是通过电解池中阴极还原氯硅烷来制取高聚物,反应条件温和,且能大大拓宽聚硅烷的功能化。本文就聚硅烷的电化学合成的实施方法;影响因素包括电解槽类型、电...     

含N、S官能基聚硅烷*

综述了近年来含N、S官能基聚硅烷的研究进展。介绍了吡啶、联吡啶、吡咯等含N官能基与噻吩、硫代官能团等含S官能基取代聚硅烷的制备和光电性能表征,概括了含N,S官能团聚硅烷的分子设计、物理性能与应用领域。最后展望了含N、S官能团聚硅烷研究的发展方向与应用前景。     

聚硅烷研究进展：（I）聚硅烷的合成及应用

聚硅烷的合成及应用因可溶性聚硅烷的发现而成为聚合物研究的又一热点。本文综述了聚硅烷合成与应用的近期发展。     

烷基芳基环聚硅烷[RArSi)n,n=5,6]的合成及其波谱性质

半个多世纪前 Kipping 最先报道了二芳基环聚硅烷(Ar_2Si)(?)的合成,其中 Ar=Ph,p-MeC_6H_4,n=4,5,6。但是直到四十年后,它们的结构才由 Gilman 证明。迄今研究最     

功能化改性聚硅烷的研究进展及应用前景

聚硅烷是一类主链由连续Si原子组成的聚合物,其主链具有类似于大π共轭的σ-σ共轭结构.这种特殊结构使得线型聚硅烷既具有与普通大π共轭导电聚合物相似的电导行为,又具有其它导电聚合物所不具备的优良溶解性和可加工性,是一类潜力巨大的功能高分子材料.但单纯聚硅烷的光致/电致发光和导电性能与其它功能高分子材料相比还不够突出,自身对水分和空气比较敏感,需要对其进行改性.本文对聚硅烷的结构与性能之间的关系进行了归纳,对聚硅烷的改性方法进行了详细分类并综述,并对聚硅烷的应用方向和研究进展进行了总结,最后对功能化聚硅烷的应用前景进行了展望.     

金属-聚哇烷-硅结构的电容-电压特性

设计了metal-polysilane-silicon(MPS)结构.首次发现MPS结构具有电容-电压(C-V)特性,许多MPS结构的C-V曲线平带电压为正,且其C-V特性与聚硅烷枝化度一致,即随着聚硅烷枝化度提高,MPS结构C-V曲线明显向电压轴正向漂移.聚硅烷MPS结构有望设计成测定聚硅烷枝化度装置.     

聚硅烷高分子化学的发展及应用

本文介绍了聚硅高分子的合成方法、紫外吸收、光敏性、导电性等一系列特殊性质,聚硅烷高分子的化学反应以及聚硅烷材料的应用.     

Contributions to the Chemistry of the Binary Compounds of the Transition Elements

Phase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen-poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is given.     

Semiconductor quantum dots and metal nanoparticles: syntheses,optical properties,and biological applications

We review the syntheses, optical properties, and biological applications of cadmium selenide (CdSe) and cadmium selenide–zinc sulfide (CdSe–ZnS) quantum dots (QDs) and gold (Au) and silver (Ag) nanoparticles (NPs). Specifically, we selected the syntheses of QDs and Au and Ag NPs in aqueous and organic phases, size- and shape-dependent photoluminescence (PL) of QDs and plasmon of metal NPs, and their bioimaging applications. The PL properties of QDs are discussed with reference to their band gap structure and various electronic transitions, relations of PL and photoactivated PL with surface defects, and blinking of single QDs. Optical properties of Ag and Au NPs are discussed with reference to their size- and shape-dependent surface plasmon bands, electron dynamics and relaxation, and surface-enhanced Raman scattering (SERS). The bioimaging applications are discussed with reference to in vitro and in vivo imaging of live cells, and in vivo imaging of cancers, tumor vasculature, and lymph nodes. Other aspects of the review are in vivo deep tissue imaging, multiphoton excitation, NIR fluorescence and SERS imaging, and toxic effects of NPs and their clearance from the body. Figure Semiconductor quantum dots and metal nanoparticles have extensive applications, e.g., in vitro and in vivo bioimaging Tamitake Itoh and Abdulaziz Anas contributed equally to this article.     

Simultaneous analysis of serotonin, melatonin, piceid and resveratrol in fruits using liquid chromatography tandem mass spectrometry

An analytical method was developed for the simultaneous quantification of serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol using reversed-phase high performance liquid chromatography coupled to mass spectrometry (HPLC-MS) with electrospray ionization (ESI) in both positive and negative ionization modes. HPLC optimal analytical separation was achieved using a mixture of acetonitrile and water with 0.1% formic acid as the mobile phase in linear gradient elution. The mass spectrometry parameters were optimized for reliable quantification and the enhanced selectivity and sensitivity selected reaction monitoring mode (SRM) was applied. For extraction, the direct analysis of initial methanol extracts was compared with further ethyl acetate extraction. In order to demonstrate the applicability of this analytical method, serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol from 24 kinds of commonly consumed fruits were quantified. The highest serotonin content was found in plantain, while orange bell peppers had the highest melatonin content. Grape samples possessed higher trans- and cis-piceid, and trans- and cis-resveratrol contents than the other fruits. The results indicate that the combination of HPLC-MS detection and simple sample preparation allows the rapid and accurate quantification of serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol in fruits.     

LOW DENSITY POLYETHYLENE/CLAY NANOCOMPOSITES MODIFIED BY ETHYLENE COPOLYMERS： EFFECTS OF FUNCTIONALIZED SEGMENTS ON MORPHOLOGY

Melt extrusion was used to prepare binary nanocomposites of ethylene copolymers and organoclay and trinary nanocomposites of low-density polyethylene （LDPE）, ethylene copolymer and organoclay. X-ray diffraction （XRD） and transmission electron microscopy （TEM） were used to analyze the structure of the clay phase and the morphology of the nanocomposites. Influences of the comonomer in the copolymer and the content of the copolymer on the morphology of the resulting nanocomposites were discussed. The binary and the trinary composites may form intercalated or exfoliated structures depending on the interaction between the copolymer and the clay layers and the content of the copolymer.     

ADSORPTION OF CHLOROFORM AND TRICHLOROETHYLENE IN WATER WITH A NEW KIND OF HYPERCROSSLINKED RESINS

In this paper two newly developed hypercrosslinked resins were used to treat micropolluted drinking water and their static and kinetic adsorption were investigated at 293 K. The results show that these two adsorbents are superior to Amberlite XAD-4 for removing chloroform and trichloroethylene in aqueous solutions. The breakthrough capacity and the total capacities from mini-column adsorption studies for chloroform and trichloroethylene on XAD-4, ZH-01 and ZH-00 are calculated respectively under experimental conditions     

Flash vacuum pyrolysis of azo and nitrosophenols: new routes towards hydroxyarylnitrenes and their reactions

Flash vacuum pyrolysis of phenylazonaphthols and nitrosonaphthols at 700°C and 0.02 Torr yielded quinoline, isoquinoline, indene and naphthols (and aniline only from the phenylazo derivatives). Similar FVP of p-nitroso and p-phenylazophenol gave pyridine. Also, FVP of phenanthraquinonemonophenylhydrazone and monooxime gave phenathridine and fluorenone. The formation of the heterocyclic system was assumed to involve nitrene and azatropone intermediates.     

二苯二硫和二苄二硫润滑性能的量子化学研究

The molecular geometries optimization and electronic structures of diphenyl disulfide (DPDS) and dibenzyl disulfide (DBDS) compounds were investigated by density functional theory (DFT) and ab initio method at the 6-31G basis set level. The active atoms and bonds of reaction were provided by frontier molecular orbital theory. The molecular orbital parameters of DPDS and DBDS compounds and iron atom cluster were calculated by using density functional theory. The interaction pattern between the organic disulfide compounds and iron atom cluster was discussed based on the approximate rule of orbital energy. Some parameters characterizing the action strength between the organic disulfide compounds and iron atom cluster, including the bonding strength, reactive strength and static action strength, were analyzed by using frontier electron density, super de-localizability, net atomic charge and the interaction energy of chemical adsorption as criteria. The results indicate that S-S chemical bond and C-S chemical bond of the compounds are inclined to be broken when DPDS and DBDS interact with the metal. The anti wear ability order of DPDS and DBDS compounds is DPDS>DBDS, and the extreme pressure ability order of DPDS and DBDS compounds is DBDS>DPDS, and the prediction results based on quantum chemistry calculations are in good accordance with the friction and wear test results.     

蛋白质、凝胶电泳及其分析应用

蛋白质是重要的生物高分子，具有催化、传输、运动、防御和调节等重要生理功能，其分离、纯化和表征对理解和利用它们在生命过程中的作用具有重大理论意义和实际价值。凝胶电泳是蛋白质测定中应用最广泛和最强有力的工具。本文讨论凝胶电泳方法及其在蛋白质分析方面的新进展。首先介绍蛋白质的性质和功能，然后讨论蛋白质试样制备方法，最后评述各种凝胶电泳分离技术及其在蛋白质分离、纯化和表征等方面的应用。     

核壳结构CdS/ZnS纳米微粒的制备与光学特性

CdS and CdS/ZnS core-shell structure nano particles were synthesized in micro emulsion, and characterized by X-ray diffraction(XRD), transmission electron microscopy (TEM), UV absorption spectra and PL. The average diameter of CdS was about 3.3 nm, and CdS/ZnS core-shell structure was confirmed by XRD and UV. Considering the optical properties of CdS/ZnS core-shell structure nanoparticles which have different ZnS shell thickness, the UV absorption edge of CdS/ZnS becomes as lightred-shift with the thickness of ZnS layer increasing, and the absorption of shortwave band is strongly enhanced at the same time. The PL spectra indicate that ZnS shell layer can greatly eliminate surface defects of CdS nanoparticles and make its band-edge directed recombination increased, and the luminous efficiency of CdS is improved greatly when it has appropriate shell thickness.